The present invention relates to a new and improved method of piecing a yarn in a friction spinning device in which freely-floating fibers are delivered in a fiber feed passage or channel to a friction spinning surface of a friction spinning means, and are transported on this friction spinning surface to a yarn formation location, from which a yarn is withdrawn.
The previously known methods and devices for the abovementioned piecing of a yarn use a yarn end drawn back from a package, which end is inserted into the stationary friction spinning means for piecing purposes so that yarn piecing is thereafter carried out at a reduced speed of the friction spinning device by feeding fibers to the returned yarn end. It has also been suggested that, before piecing, i.e. before feeding the freely-floating fibers to the inserted yarn end, the latter be untwisted by rotating the friction spinning means in the opposite direction, in order to thereby produce a better binding or interlacing of the delivered fibers with the yarn end.
A device of this general type is known from the German Patent Publication No. 3,318,687, in which a yarn end from a reverse-rotated package is taken up by a suction device, and the yarn drawn in by suction is held by two reciprocating devices in the converging gap of two stationary friction spinning drums. Before supplying freely-floating fibers to this yarn, the latter is opened or loosened by reverse rotation of the friction spinning drums, so that the fibers of the yarn lie substantially in a twist-free manner in the converging gap of the friction spinning drums. Thereafter, the friction spinning drums are set in rotation in the normal direction of rotation and at reduced speed, and freely-floating fibers are supplied to the opened yarn, the yarn thereby produced being withdrawn at a correspondingly reduced speed and fed to a connecting or piecing device or means. In order to take up the yarn continually delivered during the time required for the yarn piecing operation, the delivered yarn is taken in by a suction nozzle functioning as a yarn storage device. After completion of yarn piecing, the complete device is accelerated to operating speed and thereafter is disconnected from the required auxiliary drive means and is driven at operational speed by the normal drive means. The disadvantages of such a device lie in the multiplicity of auxiliary devices for the piecing operation.